System of electrical distribution.



B. FEANKENFIELD. SYSTEM or ELEGTRIGAL DISTRIBUTION.

APPLICATION FILED MARLSO, 1907.

93 1 ,404. Patented Aug. 17, 1909.

2 SHEETS-SHEET 1.

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I... ll 16' 1? B. FRANKENPIELD. SYSTEM OF ELECTRICAL DISTRIBUTION.

APPLICATION FILED MAR.30,1907.

Patented Aug. 17, 1909.

2 SHEETS-SHEET 2.

UNITED-STATES PATENT- ourIon.

' BUDD- FRANKENFIELD, OF NORWOOD, OHIO, ASSIGNOR TOALL'IS GHALME RS COMPANY; A

. CORPORATION OF NEW JERSEY, AND TO 'THE BULLOCK"ELEOTRIO MANUFAOTURING COMPANY, A CORPORATION OF OHIO.

sys'rnrc or.nnncrmcanms'mrnu'rrou.

No. es c404.

Specification of Letters Patent.

i ratenwan 17,1909.

Application filed March 30, 1907. ',Seria1Nc. 355,460.

To cllwhom it may concern."

.Be it known thatL-Bunn' FRANKENFIELD,

citizenv of the United States, residing at -Norwood,;. in the county of Hamilton and' -,State of Ohio, have invented certain new and --.useful. Improvements: in Systems of Elec- I trical Distribution,- ofi'which the following is a full, clear-, and exact specification.

My-..invention. relates tosystems of elec trical distribution in which a plurality of motors having shuntvfieldwindings are mechanically copnected to drive a common ;especially in the temperatures of their .field. a nets, causes a non-proportional division m of tile load even-when the speed regulation curves of the motors are normally: similar.

Asja result of. this, one of themotors-will soon be carrying an-undue share-of the load.

. I t-is the object of my present-invention to provide such electricalconnections for shunt motors mechanically connected to a common 'tion' to their. capacities, and that thisidiv-isionof the load will be stable; regardless of inequalities in the temperatures'of the different motors.

My invention therefore broadly, comprises a-pluralityof-motors mechanically connected to a-commonload, and a shunt .field winding Ifon each ofsaid motors connected .inseries with a shunt fieldwinding of another'ofsaid motors;

In applying my invention to standard shunt -motors in which the field of each motor is Wound for the full line voltage-enumbenof specific-ally different systems of connections may be used, the essential feature being that each magnetic circuit-of the fields of the motors is provided with a shunt Winding connected in series with ashunt field windin ofanotherof said motors. I It will generally be found advantageous to have the shunt field coils on ad j acent, field =polesin idiiferent electric circuits.

also be inseries with the motor shunt windings as shown. load that; theywill divide-the load inpropor- Other featuresigof my invention will appear from 'therdescription and drawi sand will be particularly, pointed out in the c aims.

Figure' 1 shows two motors mechanically .connected to a common load and electrically connected imaccordance with m invention so that themotors will-dividethe cad in proportion to their capacities; Figs. 2,3, 4=-and 5 show modifications .of the system of. conrnections.

a.-'l.he' two motonarm'atures A andlB shown in'Eig. 1 may bemech'anicall .connected to a common load in any-desire manner, as for instance; by [being on. a common shaft,..by having theiwshafts directly coupled, or by being connecterhby belts, gears,--chains or ropes to the load, here represented by a shaft 10. The two armatures A and .B are connected-in; shuntto each other and are started by a common startingbox 12,

through'which-and a switch 13 they are con-- .necte supply. The shunt field windings 14 and 15 e two motors res ectively are connected in series with'each-ot er across the line an'd' to the-common source, of current oft areadjustable instrength by the common field. rheostat 16. The no-voltage release magnet. "17- of thestarting rneostat 12 mav Upon closing the -.sw-itch:'13. and moving the arm-of the startingbox 12 to the right, the motors A and B and their common load berstarted. Bya'djustingthe rheostat 16, any desired-speedmay be obtained within the limits of speed variation of themotors.

Should the'motors be operated under different conditions, at different tem eratures for instance, any change in the fie d resistance of one varies-the field strengths of the-two machines correspondingly. This prevents either motor from-taking more than its share of'the load, as Wouldbe-the case iithe motors were independently connected to the line and the field winding of onebecame hotter arid therefore, because-oi its increased resistance, Weaker than thefield Winding of; the

other motor In the same Way any other difference in the. conditions wanderv which-the mctorsoperatedoes not cause a non-proportionai division 0t thedoad, because any electricalrchange in the field-of the-one-isaccompanied by a; correspciiding changefm, thefield of the other. In the arrangement shownin Fig. 1, however, each of the shunt field windin 14 and 15 has impressed thereon only a part of the line voltage, thus requiring the fields of these motors to be specially wound. In the other figures I have shown arrangements in which the same advantages are obtainec as in Fig. 1, while in addition standard motors may be used without reguiring any change in their field windings. n these other figures the various regulating rheostats and the mechanical connections between the motors and its common load are omitted for the sake of simplicity in the drawings, although in practice they would be necessary.

In F'g. 2 the armatures A and B of two motors are connected in shunt to each other. These two motors are bipolar motors having field poles 21 and 22 and 23 and 24, respectively. The windings on the poles 21 and 24 are connected in series, while the windings on the poles 22 and 23 are likewise connected in series, these two circuits being in shunt to each other and to the armatures. If the motors have like field windings the resistance of each of these shunt field circuits is the same as that which the field windings of a single motor separately connected in series would have.

With the arrangement of Fig. 2, any change in the conditions under which one motor operates causes corresponding electrom'agnetlc variations in the two motors. Thus any increase in the temperature of the lefthand motor increases the resistancepf the field windings on the poles 21 and 22, and this increase in resistance, while it decreases the current in said windings, correspondingly decreases the current in the windings 24 and 23 respectively. If only one of the field coils, say on pole 21, changes in resistance the magnetic circuits of both motors are still corres ondingly afi'ected.

In ig. 3 the armatures A and B of two bipolar motors are connected in shunt to each other while the entire shunt field winding of each machine is connected directly across the line. At points between the windings on the field poles 21 and 22, and those on field oles 23 and 24, there is a cross connection 25 etween the two field windings.

The arrangement shown in Fig. 3 may be used to greater advantage where the resistances of difierent parts of the field windings of the motors may be unlike. Thus any variation in the current in the field winding on the ole 21 for instance is divided between t e windings on the poles 22 and 24. This arrangement is not as efiicacious as the arran ement of Fig. 2 even in this special case, utmay sometimes be found desirable. Similar cross connections 25 may be applied to any number of motors having any number of po es In Fig. 4 the twoarmatures A and B of two four-pole motors are connected in shunt to.

tively. The windings on poles 31, 33, 37 and 35 are connected in series, while the windings on poles 32, 34, 36, and 38 are likewise connected in series. These two circuits are connected in shunt to each other and to the armaturesifand if the motors have like field coils each of said circuits has the same resistance as a circuit comprising the windings 0n the four poles of either machine would have. The windings on alternate poles of each machine are thus connected in series, while the windings on adjacent poles are in different circuits. resistance of the field coils of either motor causes corresponding changes in the field currents of both motors in substantially the iame manner as described in connection with In'Fig. 5, fourole motors A, B, C and D are shown, the eld-poles of these motors being allshown above their respective armatures for the sake of simplicity of the drawingsinst'ead of being shown in their proper laces distributed around the armatures. he field coils on the poles 41, 46, 51, and 56, are connected in series in one circuit, the coils on the poles 42, 47, 52, and 53 in series in another circuit, the coils on the poles 43,

Thus any change in the 48, 49 and 54 in series in a third circuit, and

the coilsv on the series in still anot er circuit. These four circuits are in shunt to one another and to the armatures. In each of these shunt field circuits the resistance is the same as the rcsistance which the field coils of 'a single motor connected-in series would have pro- Vided the motors have like field windings.

Any change in the conditions under which V one motor operates causes corres onding variations in the field currents in a of the motors, while if only one field-pole one machine becomes heated and its coil therefore has an increased resistance, the field current in one pole of each motor will be ccrre 'spondingly cut down. It is generally immaterial whether the coils which are in series are oles 44, 45, 50 and 55 in on like or unlike poles of the difierr 'it motors,

series with a shunt field winding on1'eaeh other motor, and moreover each magnetic circuit of the fields of the motors has at least one exciting winding, and generally two, connected in series with a shunt field winding on another mattfl' In the preferred arrangemeritsfor standard motors the field windings onadjacent poles of each machine are in difconnected in oa gaoa modifications, the statements which compare resistances are madewith reference to motors having like field coils,to show that standard motors may then be used without any change. If the motors have unlike field coils the same systems of connections can be used with the same results, but generally the field windings of the different motors would have to be rents at different voltages.

Many modifications in the ments here shown and described may be made without departing from the spirit and scope of my invention, and all modifications which involve the rinciple of my invention .I aim to cover in the following claims.

What I claim as new is v 1. In combination, a plurality of motors mechanically connected to rotate at substantially pro ortional speeds and to drive a common fdad and having their armatures P 1'6 C188 arrangeconnected in parallel, and a shunt field winding for each of said motors connected in series with a shunt field winding of another of said motors.

2. In combination, a plurality of .motors mechanically connected to rotate at substan tially pro ortional speeds and to drive a common oad and having their armatures parallel, a shunt field winding for each of said motors connected in series with a shunt field winding of another of said motors, and a common regulating means for said field windings. l

3. In combination, a plurality of motors mechanically connected to a common load and having their armatures connected in parallel, a shunt field winding for each of said motors connected in series with a shunt field winding of another of said motors, a common starting means for the motors, and a common regulating means for said field windings.

4. In combination, a plurality of motors, and shunt field windings for said motors, the shunt field windings on adjacent poles of each Irachine being connected in separate circuits and each in series with a shunt field windingpn another of said motors.

'5. In combination, a plurality of motors, and shuntfield windings for said motors, the

'shunt field'windings on alternate poles being connected in different circuits and each being in series with a field winding on another of said motors. i

6. In combination, a plurality of motors, and shunt field windings for said motors, the

- shunt field windings on alternate poles being connected in different circuits and each being in series with a field windingon alternate poles of another of said motors.

7. In combination, a plurality of motors,

proportioned for the same cur-- least two of t and shunt field windings for saidmotors, the shunt field windings onfield poles of difierent polarity on any one motor being in different circuits. I

8. In combination, a plurality of motors, and shunt field windings for said motors, the shunt field windings on field poles of different polarity on any one motor being indifferent circuits and each in series with a shunt field .winding on one of the other motors.

9. In combination, a plurality of motors, and shunt field windings for said motors, the shunt field windings on field poles of different polarity on any one motor being in different circuits and on field poles of like polarity on any one motor in the' same circuit. K

10. In combination, a plurality of motdrs, and shunt field windings for said motors, the shunt field windings on field poles of different polarity on any one motor being in different circuits and on field poles of like olarity on any one motor in the same circuit, the field winding on each pole of each motor being in series with a field winding on another of said motors.

11. In combination, a plurality of motors, and a plurality of shunt field circuits therefor equal in number to the number of motors and each including a field winding on each motor.

12. In combination, a plurality of motors, and a plurality of shunt field circuits therefor equal in number to the number of motors and each including the winding on one field pole of each of said motors. 13. In combination, a plurality of motors,

and a plurality of shunt field circuits therefor equal in number to the. number of motors, each of said shunt field circuits including shunt field windings on 14. In combination, a plurality of motors connected to a common load and having their armatures connected in parallel, each magnetic circuit of the fields of the motors being excited by a shuntfield winding connected in series with a shunt field winding of another of said motors.

15. In combination, a plurality of motors, and a plurality of shunt field circuits therefor, each magnetic circuit of the fields of the motors being excited at least two shunt field windings in different ones of said shunt field circuits, and each of said shunt field circuits com rising field windings on at 1e motors.

16. In combination, a plurality of motors two of said motors.

having their corresponding armature terminals directly connected, a shunt field winding foreach of said motors connected in series with a shunt .field winding of another of said motors, a common starting means for. the motors, and a common regulating means for said field windings.

17. In combination, aplurality of'motors mechanically connected to'rotate at substam,

tially proportional speeds and to drive a parallel, a shunt field winding for each of common load and having their armatures said motors connected in series within. shunt connected in parallel, a shunt field Winding field winding of another of said motors, and for each of said motors connected in series unitary means for regulating said two field with a shunt field Winding ofanother of said windings correspondingl motors, a common starting means for the said field windings.

18. In combination, a plurality ofrnotors I mechanically connected to a common load and having their armatures connected in In testimony whereof my signature,

motors, and a common regulating means for in the presence of two witnesses.

BUDD FRANKENFIELD:

Witnesses:

Gno B. SOHLEY, FRED J. KmsEY. 

